CN216902210U

CN216902210U - Multiplex signal input circuit, control unit and electronic device

Info

Publication number: CN216902210U
Application number: CN202123087101.1U
Authority: CN
Inventors: 黄诗友
Original assignee: Continental Automotive Body Electronic System Wuhu Co Ltd
Current assignee: Continental Automotive Body Electronic System Wuhu Co Ltd
Priority date: 2021-12-09
Filing date: 2021-12-09
Publication date: 2022-07-05
Anticipated expiration: 2031-12-09

Abstract

The utility model provides a multiplexing signal input circuit, which comprises an input end, at least a first output end and a second output end, wherein the input end is used for inputting multiplexing signals, the multiplexing signal input circuit also comprises a first circuit and a second circuit, the first circuit is arranged between the input end and the first output end, and the second circuit is arranged between the input end and the second output end. The utility model also provides a control unit and an electronic device. The multiplexing signal input circuit, the control unit and the electronic device provided by the utility model can input a plurality of control signals by using one-path input, and reduce the cost increase caused by adding input signals.

Description

Multiplex signal input circuit, control unit and electronic device

Technical Field

The utility model relates to the field of automobiles, in particular to a multiplexing signal input circuit, a control unit and an electronic device.

Background

Generally, the liquid crystal display screen inputs a wake-up signal from the outside, the voltage range of the wake-up signal is wide, for example, the input signal is 1V to 19V, and when the input signal is greater than 8V, the liquid crystal display screen is woken up and enters a working state.

In the case of the lcd, the user may need to adjust the brightness, and thus needs to adjust the brightness by an external control signal, such as a voltage signal, which requires an additional input, and accordingly, an additional external connection, and may also need to modify the structure of the housing and the connector, which will definitely bring about a higher cost.

Disclosure of Invention

The present invention is directed to a multiplexing signal input circuit, which can input a plurality of control signals by using one input path, and reduce the cost increase caused by the increase of input signals.

The utility model provides a multiplexing signal input circuit, which comprises an input end, at least a first output end and a second output end, wherein the input end is used for inputting multiplexing signals, the multiplexing signal input circuit also comprises a first circuit and a second circuit, the first circuit is arranged between the input end and the first output end, and the second circuit is arranged between the input end and the second output end.

Further, when the multiplex signal belongs to a first range, the first output terminal outputs a valid signal, and when the multiplex signal belongs to a second range, the first output terminal outputs an invalid signal, and the first range and the second range are not overlapped.

Further, the first circuit is configured to determine whether the multiplexed signal belongs to a first range, and if so, the first output terminal outputs a first level, otherwise, the first output terminal outputs a second level, where the first level is a valid signal.

Further, the first circuit includes a first voltage divider and a first diode, wherein a first reference voltage corresponding to the setting value is input to an anode of the first diode, a cathode of the first diode is connected to the first output terminal, the first voltage divider is disposed between the input terminal and the first output terminal, and if the divided voltage of the multiplexed signal is greater than the first reference voltage, the first output terminal outputs a first level, and the first level is a high level.

Further, the second circuit includes a switching circuit for controlling whether the second output terminal outputs the second voltage according to the first control signal, and a second voltage dividing circuit for dividing the voltage corresponding to the multiplexed signal.

Further, the switching circuit comprises a first triode and a second triode, the first triode is an NPN type triode, the second triode is a PNP type triode, a base of the first triode is connected with the control end Pctl through a sixth resistor, an emitting electrode of the first triode is grounded, a collecting electrode of the first triode is connected to the negative electrode of the first diode through a fifth resistor, a fourth resistor and a third resistor which are connected in series, the positive electrode of the first diode is connected with the input end Pin, a base of the second triode is connected with a connecting node of the fifth resistor and the fourth resistor, the emitting electrode of the second triode is connected with a connecting node of the third resistor and the fourth resistor, and the collecting electrode of the second triode is output to the second voltage division circuit.

Furthermore, the second circuit further comprises a port protection circuit, the port protection circuit comprises a ninth resistor and a fifth diode, the ninth resistor is arranged between the voltage division node of the second voltage division circuit and the second output end, the anode of the fifth diode is connected with the voltage division node of the voltage division circuit, and the cathode of the fifth diode is connected with the first power supply.

Furthermore, the second circuit further comprises a port protection circuit, the port protection circuit comprises a first resistor and a second diode, the first resistor is arranged between the voltage division node of the second voltage division circuit and the second output end, the anode of the second diode is connected with the voltage division node of the voltage division circuit, and the cathode of the second diode is connected with the first power supply.

The utility model also provides a control unit, which comprises a main control chip and the multiplexing signal input circuit, wherein the input end of the multiplexing signal input circuit is connected with an external signal, the first output end of the multiplexing signal input circuit is connected with the awakening pin or the enabling pin of the main control chip, the first level output by the first output end is used for awakening or enabling the main control chip, the second output end of the multiplexing signal input circuit is connected with the analog acquisition end of the main control chip, and the second voltage output by the second output end is used for controlling equipment connected with the control unit.

Furthermore, a first output pin of the main control chip is connected with an input end of a switch circuit of the second circuit, and the first output pin outputs a first control signal to control whether the second output end outputs the second voltage.

The utility model also provides an electronic device which comprises a shell, a PCB arranged in the shell and equipment connected with the control unit, wherein the PCB is provided with the control unit.

Compared with the prior art, the multiplexing signal input circuit, the control unit and the electronic device provided by the utility model have the following beneficial effects: a plurality of control signals can be input by using one input, and the cost increase caused by the increase of the input signals is reduced.

Drawings

FIG. 1 is a schematic view of a meter of one embodiment of the present invention;

fig. 2 is a schematic diagram of a multiplexed signal input circuit.

Detailed Description

An electronic device, such as a meter, according to an embodiment of the present invention includes a housing and a PCB disposed in the housing, the PCB being provided with a control unit. In other embodiments, the electronic device may also be an infotainment system, a heads-up display device, or a display device.

As shown in fig. 1, the control unit includes a main control chip Con and a multiplexing signal input circuit InC.

The multiplexing signal input circuit InC comprises an input end Pin, at least a first output end Po1 and a second output end Po2, wherein the input end Pin is used for inputting a multiplexing signal Se, the multiplexing signal input circuit InC further comprises a first circuit InC1, a second circuit InC21 and an InC22, the first circuit InC1 is arranged between the input end Pin and the first output end Po1, and the second circuit InC21 and InC22 are arranged between the input end Pin and the second output end Po 2.

An input end Pin of the multiplexing signal input circuit is connected with an external signal Se, a first output end Po1 is connected with a wake-up Pin Pwu of the main control chip Con, a first level output by the first output end Po1 is used for waking up the main control chip Con, a second output end Po2 is connected with an analog acquisition end Padc of the main control chip Con, a second voltage V2 output by the second output end Po2 is used for controlling a device connected with the control unit, for example, controlling the brightness of the display screen Dis, specifically, the output end Po4 of the main control chip Con is connected with the display screen Dis, and the main control chip Con outputs a corresponding control signal PWM (pulse width modulation) signal from the output end Po4 according to the second voltage V2 acquired by the analog acquisition end Padc to control the brightness of the display screen Dis.

The first output pin Po3 of the main control chip Con is connected to the input end Pctl of the switch circuit of the second circuit, and the multiplexing signal Se passes through the first voltage divider circuit, and the first output pin Po3 outputs the first control signal Sctl to control whether the second output terminal Po2 outputs the second voltage V2.

The first circuit InC1 includes a first voltage divider circuit formed by resistors R1 and R2 and a second diode D2, an anode of the second diode D2 is connected to a first reference voltage Vr corresponding to a set value (e.g., 8V), a cathode of the second diode D2 is connected to the first output terminal Po1, the first voltage divider circuit is disposed between the input terminal Pin and the first output terminal Po1, and if the divided voltage of the multiplexing signal Se is greater than the first reference voltage Vr, the first output terminal Po1 outputs a first level, which is a high level Vhi.

When the multiplexing signal Se belongs to the first range (8V-19V), for example, the voltage of the multiplexing signal Se is greater than or equal to the set value, specifically, the first output terminal Po1 outputs an active signal, which is a first level, i.e. a high level Vhi in this embodiment, and the first level is input to the wake-up input terminal Pwu of the main control chip Con, so as to wake up the main control chip Con.

When the multiplexing signal belongs to the second range (1-4V), for example, the low voltage range is 1-4V, the first range (8V-19V) does not overlap with the second range (1-4V), the first output terminal Po1 outputs an invalid signal, in this embodiment, the invalid signal is the second level, i.e., the low level Vlo, i.e., the wake-up input terminal Pwu of the main control chip Con inputs the low level, and does not wake up the main control chip Con, i.e., when the brightness control signal is input from the outside, the valid wake-up signal is not input, i.e., the main control chip Con is not woken up by mistake; when the multiplexing signal Se also belongs to the first range (8V-19V), the main control chip Con does not use the second voltage V2 collected by the analog collection terminal Padc as an effective brightness control signal

Therefore, the multiplexing signal input circuit InC only inputs a multiplexing signal Se from the input end Pin, can be used for awakening the main control chip Con and controlling the brightness of the display screen Dis, namely, external wiring is not increased, and the structure and the connector of the shell are not modified, so that the cost increase caused by the increase of input signals is reduced.

The second circuit comprises a switch circuit InC21, a second voltage dividing circuit InC22 composed of a seventh resistor R7 and an eighth resistor R8, the switch circuit InC21 is used for controlling whether the second output terminal Po2 outputs the second voltage V2 according to the first control signal Sctl, and the second voltage dividing circuit InC22 is used for dividing the voltage corresponding to the multiplexing signal Se so as to adapt to the input range of the analog acquisition terminal Padc of the main control chip Con.

As shown in fig. 2, the switching circuit InC21 includes a first transistor T1 and a second transistor T2, the first transistor T1 is an NPN transistor, and the second transistor T2 is a PNP transistor.

The base of the first triode T1 is connected with the control terminal Pctl through a sixth resistor R6, the emitter is grounded, the collector is connected to the cathode of the first diode D1 through a fifth resistor R5, a fourth resistor R4 and a third resistor R3 which are connected in series, and the anode of the first diode D1 is connected with the input terminal Pin.

The base of the second triode T2 is connected to the connection node of the fifth resistor R5 and the fourth resistor R4, the emitter is connected to the connection node of the third resistor R3 and the fourth resistor R4, and the collector outputs to the second voltage divider circuit.

When the control signal Sctl inputted from the control terminal Pctl is at a high level, the first transistor T1 is turned on, and its collector is grounded; at this time, the third resistor R3, the fourth resistor R4 and the fifth resistor R5 have current flowing through them, because the base and the emitter of the second triode T2 are connected to the two ends of the fourth resistor R4, the voltage difference across the fourth resistor R4 makes the second triode T2 conductive, the multiplexing signal Se is output to the second voltage dividing circuit, and then the second output terminal Po2 outputs the second voltage V2 to control the analog collecting terminal Padc of the chip Con.

When the control signal Sctl input from the control terminal Pctl is at a low level, the first transistor T1 is turned off, and the second output terminal Po2 does not output the control signal Sctl.

The switching circuit InC21 further includes a third diode D3 connected in parallel to the first transistor T1, and a fourth diode D4 connected in parallel to the second transistor T2 for including a corresponding transistor, for example, the multiplexing signal Se applies-60V during testing.

The second circuit further includes a port protection circuit, in this embodiment, the port protection circuit includes a ninth resistor R9 and a fifth diode D5, the ninth resistor R9 is disposed between the voltage dividing node of the second voltage dividing circuits R7 and R8 and the second output terminal Po2, and limits the output current of the second output terminal Po2, an anode of the fifth diode D5 is connected to the voltage dividing node of the voltage dividing circuits R7 and R8, and a cathode of the fifth diode D5 is connected to the first power supply Vcc for limiting the output voltage of the second output terminal Po2, so as to protect the analog acquisition terminal Padc of the main control chip Con, for example, during a test, the multiplexing signal Se applies a voltage of 40V.

In order to reduce the cost increase caused by the addition of the input signal, in the new scheme, the voltage value of the wake-up signal input from the outside, such as 1-4V, is utilized to perform corresponding logic control, such as adjusting the brightness of the liquid crystal display screen.

But at the same time it is necessary to monitor this signal (the low voltage is monitored accurately because the LCD screen needs to know this external signal, in particular the low voltage value, on which the LCD screen adjusts the brightness of the LCD, for example). This voltage value is monitored and is usually converted into an analog quantity, because the low voltage cannot take a very small value due to the processing accuracy of the chip (in practical terms, the noise effect is also considered, and usually several tens of millivolts are available).

In another embodiment, the enable signal and the control signal may be multiplexed, for example, the controller enable signal and the brightness control signal of the lcd panel may be multiplexed.

In yet another embodiment, a third output and a third circuit may be further included, which may be used as another control signal when the multiplexed signal Se belongs to a third range (4V-8V).

Although the present invention has been described with reference to the preferred embodiments, it is not limited thereto. Various changes and modifications within the spirit and scope of the present invention will become apparent to those skilled in the art from this disclosure, and it is intended that the scope of the present invention be defined by the appended claims.

Claims

1. The multiplexing signal input circuit is characterized by comprising an input end, at least a first output end and a second output end, wherein the input end is used for inputting multiplexing signals, the multiplexing signal input circuit further comprises a first circuit and a second circuit, the first circuit is arranged between the input end and the first output end, and the second circuit is arranged between the input end and the second output end.

2. The multiplexed signal input circuit of claim 1, wherein the first output terminal outputs an active signal when the multiplexed signal falls within a first range, and outputs an inactive signal when the multiplexed signal falls within a second range, the first range and the second range being non-overlapping.

3. The multiplexed signal input circuit of claim 2 wherein the first circuit is configured to determine whether the multiplexed signal falls within a first range, and if so, the first output terminal outputs a first level, and otherwise outputs a second level, wherein the first level is a valid signal.

4. The multiplexed signal input circuit of claim 3, wherein the first circuit includes a first voltage divider circuit and a first diode, an anode of the first diode inputs a first reference voltage corresponding to the setting value, a cathode of the first diode is connected to the first output terminal, the first voltage divider circuit is disposed between the input terminal and the first output terminal, and if the multiplexed signal is divided by more than the first reference voltage, the first output terminal outputs a first level, and the first level is high.

5. The multiplexed signal input circuit of claim 1, wherein the second circuit includes a switching circuit for controlling whether the second output terminal outputs the second voltage according to the first control signal and a second voltage dividing circuit for dividing the voltage corresponding to the multiplexed signal.

6. The multiplexing signal input circuit of claim 5 wherein the switching circuit comprises a first transistor and a second transistor, the first transistor is an NPN transistor, the second transistor is a PNP transistor, the base of the first transistor is connected to the control terminal Pctl through a sixth resistor, the emitter is grounded, the collector is connected to the cathode of the first diode through a fifth resistor, a fourth resistor and a third resistor connected in series, the anode of the first diode is connected to the input terminal Pin, the base of the second transistor is connected to the connection node of the fifth resistor and the fourth resistor, the emitter is connected to the connection node of the third resistor and the fourth resistor, and the collector is output to the second voltage divider circuit.

7. The multiplexed signal input circuit of claim 6, wherein the second circuit further comprises a port protection circuit, the port protection circuit comprising a ninth resistor and a fifth diode, the ninth resistor being disposed between the voltage dividing node of the second voltage dividing circuit and the second output terminal, the fifth diode having an anode connected to the voltage dividing node of the voltage dividing circuit and a cathode connected to the first power supply.

8. A control unit, comprising a main control chip and the multiplexing signal input circuit of any one of claims 1-7, wherein an input terminal of the multiplexing signal input circuit is connected to an external signal, a first output terminal is connected to a wake-up pin or an enable pin of the main control chip, a first level output by the first output terminal is used for waking up or enabling the main control chip, a second output terminal is connected to an analog acquisition terminal of the main control chip, and a second voltage output by the second output terminal is used for controlling a device connected to the control unit.

9. The control unit of claim 8, wherein a first output pin of the main control chip is connected to an input terminal of the switching circuit of the second circuit, and the first output pin outputs a first control signal to control whether the second output terminal outputs the second voltage.

10. An electronic device, characterized in that the electronic device comprises a housing, a PCB board arranged in the housing, the PCB board being provided with a control unit according to claim 8 or 9, and a device connected to the control unit.